US4384919A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making x-ray masks
Assignee: Unisys Corp
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Filing: 1980-07-25
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Granted: 1983-05-24
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Expires: 2000-07-25
Abstract
Abstract An x-ray mask is made by forming a thin polyimide membrane on a silicon wafer substrate which is then back-etched to form a mask supporting ring of the substrate.
Inventors
- 👤 Martin J. Casey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:43
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/22
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
104 words
The method of making an x-ray mask or the like which comprises the steps of: forming a roughened rim around the outside edge of a polished front side of a wafer-shaped mask-supporting substrate; applying a thin coating of a transparent film layer directly onto the surface of said front side of said substrate; forming an absorber pattern directly on the exposed surface of said film layer; and etching said substrate on its backside to etch away all but a supporting ring of substrate extending around the peripheral edge of said film layer so as to form a membrane with the absorber pattern contained thereon.
Claim 2
Independent Claim
104 words
The method of making an x-ray mask or the like which comprises the steps of: forming a roughened rim around the outside edge of a polished front side of a wafer-shaped mask-supporting substrate; applying a thin coating of a transparent film layer directly onto the surface of said front side of said substrate; forming an absorber pattern directly on the exposed surface of said film layer; and etching said substrate on its backside to etch away all but a supporting ring of substrate extending around the peripheral edge of said film layer so as to form a membrane with the absorber pattern contained thereon.
Claim 3
Dependent Claim
23 words
The method according to claim 1 wherein the membrane formed is about two microns thick and said substrate is about 250-375 microns thick.
Claim 4
Dependent Claim
16 words
The method according to claim 1 wherein said roughened rim is formed by a sandblasting operation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |